1. Field of Invention
The present invention relates to resistance measuring filed, and more particularly to a resistance measuring apparatus for measuring static resistance and dynamic resistance variation and its method.
2. Description of Related Arts
At present according to different volume resistivity ρ, there are two methods for measuring resistance. When ρ<108Ω·cm, a normal intelligent digital multimeter is enough to measure resistance, while when ρ>108Ω·cm, an ultra-high resistance meter is needed to measure resistance. This means, when the external environment (load, temperature, humidity, corrosion, aging, etc.) has changed dramatically, the resistance of a material will change greatly, even that the order of magnitude of the resistance changes greatly. In this case, two different apparatus are needed to measure the resistance. However, during measurement process, changing measuring apparatus not just results in more operation, but needs time interval. Therefore, for a same material, these shortcomings will lead to error in resistance measurement.
With the rapid development of aerospace industry, the researches on new material with lightweight and shielding properties have advanced. Research staff are focusing on polypropylene, polyaniline and other polymers. After adding conductive particles, the electrical properties of these polymer materials have very important significances to study the internal mechanism of the material conductivity under loading. In order to measure the resistance of these materials, the ultra-high resistance meter is usually used. However, the actual result of measurement is not satisfactory. Limited by internal circuit structure of the ultra-high resistance meter, only a roughly resistance value can be gained, and the gained roughly value often has a large deviation, Therefore, accuracy measurement is a problem to be solved.
In a relatively short period of time, when loading on the measured object, the measured physical quantity of the measured object will generate a fast and great variation. Then, write down this variation. If the measured physical quantity is the resistance of the measured object, the above measurement process is called dynamic measurement of the resistance. At present, the existing resistance measurement apparatus is mainly used for static measurement, and not able to take a dynamic measurement by reason that the dynamic load variation is too short to be measured (required measurement frequency is 1 per second). That is, the dynamic load variation is already finished before the resistance measurement apparatus to acquire related data. Up to now, dynamic measurement of the resistance is still a problem remaining to be solved.